• ETRI Journal
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• v.26 no.1
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• pp.13-20
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• 2004

We propose a new optical code division multiple access (OCDMA) scheme for reducing multiple access interference (MAI) and enhancing performance for optical subscriber access networks using modified pseudorandom noise (PN)-coded fiber Bragg gratings with bipolar OCDMA decoders. Through the bipolar OCDMA decoder and the modified PN codes, MAI among users is effectively depressed. As the data are encoded either by a unipolar signature sequence of the modified PN code or its complement according to whether the data bit is 1 or 0, the bit error ratio (BER) can be more improved with the same signal to interference plus noise ratio over the conventional on-off shift keying-based OCDMA system. We prove by numerical analysis that the BER of the proposed bipolar OCDMA system is better than the conventional unipolar OCDMA system. We also analyze the spectral power distortion effects of the broadband light source.

• International Journal of Advanced Culture Technology
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• v.7 no.2
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• pp.103-112
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• 2019

Online self-disclosure was hypothesized as a mediating variable, explaining the relationship between Facebook access motivation (relationship expansion, curiosity about others' life, maintenance of social connection, social pressure from others, habitual use, impression management, searching for information, and content sharing) and Facebook addiction. Data came from 407 high school students in the Busan, and Gyeongnam provinces. Structural analysis was used to specify the relations among measured construct. Facebook access motivation of curiosity about others' life, Facebook access motivation of maintenance of social connection, Facebook access motivation of social pressure from others, Facebook access motivation of habitual use, and Facebook access motivation of impression management were significant predictors of Facebook addiction. Online self-disclosure mediates between Facebook access motivation of curiosity about others' life, Facebook access motivation of social pressure from others, Facebook access motivation of searching for information & Facebook access motivation of content sharing and Facebook addiction. Viewing online self-disclosure as a mediator has important implications for social media addiction counseling practice.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.8-18
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• 2010

As Ubiquitous systems are developed, the number of context data which are dealt with systems also grow rapidly. In these data, some are vary important in privacy view. As these data are given to users or services of systems, probability of excess exposing of data is exist. To solve this problem, many systems use access control method like RBAC. But even this method can avoid unauthenticated access, can not prevent excess exposing of authenticated access. To prevent this exposing of context data, this paper suggests context data access control framework which abstracts context data when system gives these data to users or services. Using negotiation protocol and context data abstraction technique using RDF, our framework prevents excess exposing important data. This happens protecting privacy and keeping service continuity.

• Journal of Korean Library and Information Science Society
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• v.47 no.3
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• pp.213-239
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• 2016

As Open Data has been emphasized globally, discussions on data policies have occurred for minimizing problems resulting from data sharing and reuse. This study aimed at investigating policy components for controlling access and use of data and examining similarities and differences of the policy components across disciplines. For the purpose, the study analyzed policy components for data access and use controls provided by 37 research data repositories overseas. These included twenty repositories in biological and health science, ten in chemistry, earth and environmental science and physics, as well as seven in social science and general science. The analysis showed that common policy components involve copyright/licenses, data citation, disclaimers and embargoes. However, there were differences in diversity of policy components among the disciplines and it indicated that the rationales of access and use controls emphasized would be different in the disciplines.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.9
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• pp.2550-2572
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• 2023

Epidemiological survey is an important means for the prevention and control of infectious diseases. Due to the particularity of the epidemic survey, 1) epidemiological survey in epidemic prevention and control has a wide range of people involved, a large number of data collected, strong requirements for information disclosure and high timeliness of data processing; 2) the epidemiological survey data need to be disclosed at different institutions and the use of data has different permission requirements. As a result, it easily causes personal privacy disclosure. Therefore, traditional access control technologies are unsuitable for the privacy protection of epidemiological survey data. In view of these situations, we propose a black box-assisted fine-grained hierarchical access control scheme for epidemiological survey data. Firstly, a black box-assisted multi-attribute authority management mechanism without a trusted center is established to avoid authority deception. Meanwhile, the establishment of a master key-free system not only reduces the storage load but also prevents the risk of master key disclosure. Secondly, a sensitivity classification method is proposed according to the confidentiality degree of the institution to which the data belong and the importance of the data properties to set fine-grained access permission. Thirdly, a hierarchical authorization algorithm combined with data sensitivity and hierarchical attribute-based encryption (ABE) technology is proposed to achieve hierarchical access control of epidemiological survey data. Efficiency analysis and experiments show that the scheme meets the security requirements of privacy protection and key management in epidemiological survey.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.239-250
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• 2019

An individual's health data is very sensitive and private. Such data are usually stored on a private or community owned cloud, where access is not restricted to the owners of that cloud. Anyone within the cloud can access this data. This data may not be read only and multiple parties can make to it. Thus, any unauthorized modification of health-related data will lead to incorrect diagnosis and mistreatment. However, we cannot restrict semipublic access to this data. Existing security mechanisms in e-health systems are competent in dealing with the issues associated with these systems but only up to a certain extent. The indigenous technologies need to be complemented with current and future technologies. We have put forward a method to complement such technologies by incorporating the concept of blockchain to ensure the integrity of data as well as its provenance.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.113-120
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• 2009

XML can supply the standard data type in information exchange format on a lot of data generated in running database or applied programs for a company by using the advantage that it can describe meaningful information directly. Therefore, as it becomes more and more necessary to manage and protect massive XML data in an efficient way, the development of safe XML access control techniques needs a new method. In this study access authorization policies are defined to design access control systems. The findings demonstrated that algorithm suggested in this study improved system performance which was low due to the complex authorization evaluation process in the existing access control techniques. It is consequently proved that the safe XML access control policy presented in this study is in an improved form as compared with the existing access control methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.171-180
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• 2013

Data security is always an important issue. In particular, the current emerging cloud computing system inevitably raises the issue of data security. However, data security is no longer safe with a simple way, but requires rather advanced method to secure the data. In this paper, instead of exploiting the existing text-based cryptography approach an image-based access control of data content is studied to present a higher level of data security. Color key chain is generated both using histogram value of the original image, and the location information and featured color information extracted by geometric transformation to form the security key to access secure data content. Finally, the paper addresses design interface and implementation for data content access control for evaluation of the proposed scheme.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.405-413
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• 2016

To solve various problems of the Internet as well as to enhance network performance, various future Internet architectures utilize cached data in network nodes or in proxy servers. Named-data networking (NDN), one of future Internet architectures, implements in-network data caching functionality, and then responds itself to request messages. However, it can cause users' privacy invasion that the publisher of data can not engage in the sharing/using process of the data anymore after the data was cached in-network. So NDN implements both encryption-based access control and group access control. But, since such access control schemes need to exchange additional messages in order to search for a proper access control list and keys, it causes inefficiency. This paper surveys the access control schemes of NDN, and then proposes an improved scheme.

• International Journal of Knowledge Content Development & Technology
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• v.9 no.4
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• pp.47-68
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• 2019

The study investigates the utilization of open access repositories for visibility of academic publications by lecturers in South-East, Nigeria. The specific objectives were to investigate the types of academic publications available, platforms used in self-archiving, level of satisfaction derived by lecturers with the contribution of open access repositories, challenges and strategies. It adopted descriptive survey design. Proportionate stratified sampling technique was used to draw a sample size of 418 from the total population of 4,187 lecturers. Questionnaire and observation check list were used for data collection. Frequency count, percentage, and mean score were used to analyze the data. The study revealed that there are enough academic publications available such as books, journals, projects, and thesis with the exception of handouts. It also revealed that Google Scholar, Research Gate and Open Access Journal were the main platforms lecturers use in self-archiving; while other platforms like Institutional Repositories, among others were minimally employed. Lecturers are less satisfied with the contribution of open access repositories. All the suggested challenges such as inadequate power supply, poor network, lack of awareness and inadequate research grants were all accepted. Similarly, all the suggested strategies for improving them were accepted. Recommendations were made based on the findings such as more awareness creation on importance of open access repositories; re-training of lecturers and provision of adequate ICT infrastructures that will improve the utilization of open access repositories by lecturers which could enhance the global visibility of academic publications from the Nigerian Universities.